Refrigerated display case



REFR IGERATED DISPLAY CASE Filed Oct. 4, 1965 2 Sheets-Sheet l Lzmmzzu J. EERWBUK. I I E l a 9 BY F I NVENTOR.

June 13, 1967 L. J. GERWECK V 3,324,676

REFRIGERATED DISPLAY CASE Filed Oct. 4, 1965 2 Sheets-Sheet 2 INVENTOR: V LEUNARD J. Emu/MK.

EZF 72/ .ATTYs.

United States Patent 3,324,676 REFRIGERATED DISPLAY CASE Leonard J. Gerweck, Kendallville, Ind., assignor to Mctlray Refrigerator Company, Inc., Kendallville, Ind., a corporation of Indiana Filed Oct. 4, 1965, Ser. No. 492,655 Claims. (Cl. 62-256) This invention relates to a refrigerated display unit or case for foods and the like, and is directed particularly to means for maintaining a comfortable ambient zone in front of the unit and for warming air used in an air curtain supplied across the front of the unit.

Upright refrigerated food cases or display units with a plurality of vertically disposed shelves and open fronts are now in common use. Such refrigerated food display units have tended to increase substantially sales of the products carried therein because the products are carried closer to the eye level of the customer so as to be noticed readily and are positioned so that it is easier for the customer to reach in and pick up the food packages.

In these cases, the temperature adjacent the shelves is often maintained at or below zero degrees F. while the ambient temperature several inches away may be seventy degrees F. or higher. The cold air is usually supplied to the area adjacent the shelves from the rear thereof with this air flowing downwardly in front of the shelves and re-circulated through suitable refrigerating apparatus by a return duct having an inlet located at the front of the unit immediately below the opening. Frequently, an outer curtain of air is supplied across the access opening of the display unit in front of the shelves to retain more effectively the cold air in the unit and separate it from the ambient air. The air of the outer curtain often is recirculated through a separate, outer return duct to an outlet located near an upper edge of the front access opening. The air is received from a second inlet located below the access opening toward the ambient from the first inlet.

In practice, some of the cold air from the display units frequently flows over the front wall thereof below the access opening and creates an uncomfortable Zone at the lower portion of the unit where the customer must stand while making his selection therefrom. This cold air is uncomfortable on the feet of the potential consumer and has a tendency to drive him away from in front of the case and defeat the main purpose of this type of refrigerated display unit, namely of increasing sales. With units of this type, there also has been a tendency for the air recirculated through the return duct for the air curtain to condense moisture in and on this duct under certain ambient conditions.

The present invention relates to an improved upright refrigerated display unit which substantially decreases or eliminates the cold zone normally found in front of the unit, and also eliminates condensation in or on the return duct of the display unit. These improvements are achieved by the use of a heating element located along the top of a reach-in rail extending along the unit immediately below the access opening of the display unit. The heating element thereby warms the cold air as it spills over the front edge of the case. A cover or cap is located around the element to prevent customer contact. In a specific form, the cap is part of the top of the reach-in rail with the front and back portions of the rail cap provided with openings to receive a portion of cold air of the curtain from the back and to expel it from the front where it can warm the lower zone in the front of the unit. In a specific form, the heating element also is located in heat exchange relationship with the air flow- "ice ing through the return duct to heat this air and prevent the possibility of condensation in or on the duct.

It is, therefore, a principal object of the invention to provide an upright refrigerated display unit having a warmer, more comfortable area near the floor in front of the unit.

Another object of the invention is to provide an upright refrigerated display unit with air flowing downwardly in front of the shelves of the unit and with means for substantially eliminating the possibility of condensation in or on a return duct for the air.

Still another object of the invention is to provide means for warming the air tending to spill over the front wall of a refrigerated display unit.

Other objects and advantages of the invention will be apparent from the following detailed description of pre ferred embodiments thereof, reference being made to the accompanying drawings, in which:

FIG. 1 is an overall view in vertical cross section of one form of an upright refrigerated display unit embodying the invention;

FIG. 2 is a fragmentary, enlarged view in vertical cross section of a lower front wall of the unit shown in FIG. 1;

FIG. 3 is a further enlarged view in vertical cross section of an upper portion of the front wall shown in FIG. 2; and

FIG. 4 is a view similar to FIG. 3 of a slightly modified embodiment of the invention.

Referring to the drawings, and more particularly to FIG. 1, one suitable upright refrigerated display unit or case 10 embodying the invention includes one or more vertically-spaced shelves 12 and a lower shelf or bottom 14 located below the shelves 12 and extending forwardly thereof. A substantial portion of the front of the unit 10 is unobstructed to provide an access opening defined by side walls 16, an upper wall 18, and a lower front wall 20. This renders it very easy for a customer to reach in and remove refrigerated food packages designated F1, F2, and F3 located on the shelves 12 and 14. Cold air is supplied to the areas above each of these shelves through an upper supply chamber 22, and two lower shelf chambers 24 having perforations through which the air is emitted. The air is supplied to these chambers from a rear supply duct 26 defined by the side Walls 16, a rear wall 28 of the unit, and an insulating divider wall 30. The supply duct 20 communicates with a lower return duct 32 defined by the side walls 16, the lower shelf 14, and a lower dividing wall 34. The return duct 32 communicates with an inlet duct 36 in the front wall 20 of the unit and defined by an inner front wall 38 and a front dividing wall 40. An inlet 42 is located at the top of the front wall 20 inwardly of a reach-in rail 44 having a cover or cap 46. Cold air is drawn through the inlet 42 by a fan 48 with the air being forced through one or more refrigerating coils 50 to cool the air to the desired temperature in order to keep the area adjacent the shelves 12 and 14 at approximately zero degrees F., for example. Refrigerant is supplied to the coils 50 by a suitable compressor unit usually remotely located and often large enough to supply a num ber of the coils 50. The first coil is designed to bring the air temperature below the dewpoint to extract as much moisture as possible. This substantially eliminates frost or condensation on the second coil. These coils are then periodically defrosted with the water draining through a suitable lower line 52.

The cold air supplied through the chambers 22 and 24 flows downwardly in front of the shelves 12 to the inlet 42. In doing so, this air ordinarily tends to be warmed considerably by contact with the ambient air immediately in front thereof. It has been discovered, however, that the temperature of this cold air can be maintained substantially lower by using an outer curtain of air in front of the inner cold air. Toward this purpose, the specific unit shown is provided with upper air curtain outlets 54 and 56 extending across the top of the unit at the upper edge of the access opening. Air is supplied to the outlets 54 and 56 through a supply duct 58 defined by an upper dividing wall 60 and an outer case wall 62. The air is moved by a suitable circulating fan 64 through a rear duct 66 which is defined by the insulating divider wall and a rear case wall 68. The duct 66 communicates with a lower return duct 70 defined by the lower dividing wall 34 and a base 72. The duct 70, in turn, communicates with a front return duct 74 located in the front wall 20 and defined by the front dividing wall and an outer case wall 76. The front duct 74 extends up the front wall 20 to the reach-in rail 44. In the embodiment shown, the rail cap 46 forms an inlet for the air curtain ductwork or passage and specifically the front duct 74 by virtue of a plurality of openings or inlets 78 located at the rear of the cap. The inlets face rearwardly and are positioned immediately above the cold air inlet 42 so as to receive the air of the warmer air curtain flowing downwardly from the outlets 54 and 56 in front of the cold air.

The rail cap 46 has a plurality of openings or outlets 80 located in front thereof, on the side opposite the inlets 78. The outlets 80 receive and dispose of a part of the air entering a heating chamber or space 82 from the inlets 78, the chamber defined by the upper portion of the cap 46, with this air tending to flow downwardly in front of the wall 20. A central electrical heating unit or element 84 extends longitudinally of the rail 44, generally centrally within the cap or cover 46 and near the bottom of the chamber 82, the cap protecting customers from direct contact with the element 84. This unit is supplied with electricity and heated by resistance and, in turn, warms the cap 46 and the air flowing through the chamber 82 from the inlets 78 to the outlets 80, as well as warms the air supplied to the duct 74, in this instance. The warm air flowing through the outlets 80 thereby is effective to increase the temperature of the lower zone or area immediately in front of the wall 20 and tends to warm the customer standing in front of the case. The customer is not subjected to the uncomfortable cold air normally spilling over the front of such cases and he has no desire to hurry away from the unit, thereby decreasing potential sales. The heating element 84 also warms the cap 46 and prevents undesirable cold contact in the event that a customer touches the cap upon reaching into the unit. With the design shown, the heating element 84 also increases the temperature of the air flowing through the ductwork for the outer air curtain and prevents condensation in or on this ductwork which can otherwise occur. This is particularly true because the air flowing through the outer ductwork is cooled to some extent by the cold air supplied through the inner ductwork, even though the wall therebetween is insulated. The temperature of the air in the outer ductwork thereby is decreased significantly by the time it reaches the outlet openings 54 and 56 and will sometimes cause condensation to form.

A slightly modified reach-in rail '86 for the display unit is shown in FIG. 4. In this instance, .a cover or cap 88 has a partition 90 located within the reach-in rail 86 and physically separates an upper chamber 92 from the upper portion of the duct 74 so that air flowing through the chamber 92 from an upper inlet 94 to an outlet 96 is physically .separatedfrom the air flowing through a lower inlet 98 to the duct 74. A heating element 100 is supported by the partition 90 with the heating element 100 warming the air supplied through the lower inlet 98 t0 the duct 74; at the same time the element is in heat exchange relation with the partition90 to heat it and in turn warm the air supplied to the chamber 92. An additional heating element can be used above the partition, if desired.

Various types of heating means may be employed as the heating element or elements other than an electrical heating element. For example, a high temprat-ure fluid line from the refrigeration unit may be employed.

Various modifications of the above described embodiments of the invention will be apparent to those skilled in the .art, and it is to be understood that such modifications can be made without departing from the scope of the invention, if they are within the spirit and the tenor of the accompanying claims.

I claim:

1. An upright refrigerated display unit having a front access opening, said front access opening being defined by side walls, an upper wall, and a lower front wall, said front wall terminating at a reach-in rail at the lower edge of said access opening, a heating element extending longitudinally of said reach-in rail at an upper portion thereof, and a protective cap extending around said heating element, said cap having a plurality of openings therein.

2. An upright refrigerated display unit having a front access opening, said front access opening being defined by side walls, an upper wall, and a lower front wall, said front wall terminating at a reach-in rail at the lower dge of said access opening, .a heating element extending longitudinally of said reach-in rail at an upper portion thereof, and a protective cap extending around said heating element, said cap having inlets on the side of said reach-in rail facing the interior of said unit for supplying air to the interior of said cap, and said cap having outlets on the side of said rail facing opposite said inlets for enabling the flow of the air from said cap to an area in front of the display unit.

3. An upright refrigerated display unit having a front access opening; means for supplying cold air to the interior of said unit; means forming a heating chamber having an inlet near the bottom edge of said access opening, and having an outlet directed toward the ambient in front of and below said access opening; and heating means in heat transfer relation with said heating chamber for heating air flowing in said inlet.

4. An upright refrigerated display unit having a front access opening, said front access opening being defined by side walls, an upper wall, and a lower front wall of said unit, said front wall terminating at a reach-in rail at the lower edge of said access opening, means for supplying cold air to the interior of said unit, a cold air return passage having an inlet inside said unit near said reach-in rail, a cold air passage directing air from said inlet back into said unit, said reach-in rail having a cap with an inlet on the side of said rail facing the interior and an outlet on the side of said rail facing the ambient, said cap forming a heating chamber between said inlet and said outlet, and a heating element extending longitudinally in said reach-in rail and in heat exchange relation with said heating chamber.

5. An upright refrigerated display unit having at least one shelf and a front access opening; means for supplying cold air to the interior of said unit; means for supplying an air curtain downwardly across said opening including means forming an air curtain outlet at the upper edge of said access opening, means forming an air curtain inlet at the lower edge of said opening, and means forming an air curtain return passage to direct air from said inlet to said outlet; means forming a heating chamber having an outlet directed toward the ambient in front of and below said opening and having inlet means communicating with said chamber and said return passage; and heating means for heating air flowing in said inlet means.

6. An upright refrigerated display unit having a plurality of vertically-spaced shelves and a front access opening; means for supplying cold air to the interior of said unit; means for supplying an air curtain downwardly across said opening in front of said shelves including means forming an air curtain outlet at the upper edge of said access opening, means forming an air curtain inlet at the lower edge of said opening, and means forming an air curtain return passage to direct air from said inlet to said outlet; means forming a heating chamber having an inlet adjacent said air curtain inlet toward the ambient from said air curtain inlet, and having an outlet directed toward the ambient in front of and below said access opening; and heating means adjacent said air curtain inlet and said heating chamber for heating air flowing in said inlets.

7. An upright refrigerated display unit having a plurality of vertically-spaced shelves and a front access opening; means for supplying cold air to the interior of said unit adjacent said shelves including outlet means in said unit, means forming a cold air inlet near the bottom edge of said opening, and means forming a cold air return passage located to direct air from said cold air inlet to said outlet means; means for supplying an air curtain downwardly across said opening in front of said shelves and including means forming an air curtain outlet at the upper edge of said access opening, and an air curtain return passage to direct air to said air curtain outlet; means forming a heating chamber having an outlet directed toward the ambient in front of and below said opening and an inlet means communicating with said heating chamber and said return passage; and heating means adjacent said air curtain inlet and said heating chamber for heating air flowing in said air curtain inlet and said heating chamber inlet.

8. An upright refrigerated display unit having a plurality of vertically-spaced shelves and a front access opening; means for supplying cold air to the interior of said unit adjacent said shelves including outlet means in said unit, means forming a cold air inlet near the bottom edge of said opening, and means forming a cold air return passage located to direct air from said cold air inlet to said outlet means; means for supplying an air curtain downwardly across said opening in front of said shelves and including means forming an air curtain outlet at the upper edge of said access opening, means forming an air curtain inlet at the lower edge of said opening toward the ambient from said cold air inlet, and means forming an air curtain return passage located to direct air from said air curtain inlet around said unit to said air curtain outlet; means forming a heating chamber having an inlet adjacent said air curtain inlet and having an outlet directed toward the ambient in front of and below said opening, and heating means adjacent said air curtain inlet and said heating chamber for heating air flowing in said air curtain inlet and said heating chamber inlet.

9. An upright refrigerated display unit having a front access opening, said front access opening being defined by side walls, an upper wall, and a lower front wall, said front wall terminating at a reach-in rail at the lower edge of said access opening, means for supplying an air curtain downwardly across said opening in front of said unit including outlet means at the upper edge of said opening, means forming an air curtain return passage communicating with said air curtain outlet means at the upper edge of said access opening, said reach-in rail forming a heating chamber at the upper extremity thereof, said reach-in rail having a plurality of inlets on the side of said rail facing the interior of said unit for supplying air to said heating chamber and said air curtain retum passage, said reach-in rail having outlet means communicating with said heating chamber on the side facing opposite said inlets, and a heating element extending longitudinally in said reach-in rail and in heat exchange relation with said heating chamber and with said air curtain inlet.

10. An upright refrigerated display unit having a front access opening, said front access opening being defined by side walls, an upper wall, and a lower front wall, said front wall terminating at a reach-in rail at the lower edge of said access opening, means for supplying an air curtain downwardly across said opening in front of said unit including outlet means at the upper edge of said opening, means forming an air curtain return passage communicating with said air curtain outlet means at the upper edge of said access opening, said reach-in rail forming a heating chamber at the upper extremity thereof, said reach-in rail having a plurality of inlets on the side of said rail facing the interior of said unit for supplying air to said heating chamber and said air curtain return pas sage, and an electric heating element extending longitudinally in said reach-in rail and in heat exchange relation with said heatingchamber and with said air curtain inlet.

11. An upright refrigerated display unit having one or more vertically-spaced shelves and a front access opening, said front access opening being defined by side walls, an upper wall, and a lower front wall of said unit, said front wall terminating at a reach-in rail at the lower edge of said access opening, means for supplying cold air to the interior of said unit adjacent said shelves, means for supplying an air curtain downwardly across said opening in front of said shelves including outlet means at the upper edge of said opening, a cold air return passage having an inlet inside said unit near said reach-in rail, a cold air passage directing air from said inlet back into said unit, means forming an air curtain return passage communicating with said air curtain outlet at the top of said access opening, said reach-in rail forming a heating chamber, said reach-in rail having a plurality of inlets on the side of said rail facing the interior and communicating with said air curtain return passage and said heating chamber, and a plurality of outlets on the side of said rail facing the ambient and communicating with said heating chamber, an electric heating element extending longitudinally in said reach-in rail and in heat exchange relation with said heating chamber and with said air curtain inlet.

12. A refrigerated display case according to claim 11 characterized by a partition extending between said heating chamber and a portion of said air curtain return passage.

13. An upright refrigerated display unit having a plurality of vertically-spaced shelves and a front access opening, said front access opening being defined by side walls, an upper wall, and a lower front wall of said unit, said front wall terminating at a reach-in rail at the lower edge of said access opening, means for supplying cold air to the interior of said unit adjacent said shelves, means for supplying an air curtain downwardly across said opening in front of said shelves including outlet means at the upper edge of said opening, a cold air return passage having an inlet inside said unit near said reach-in rail, a cold air passage directing air from said inlet back into said unit, means forming an air curtain inlet between said firs-t inlet and the top of said reach-in rail, means forming an air curtain return passage communicating with said air curtain inlet and said air curtain outlet at the top of said access opening, said air curtain return passage carrying air from said air curtain inlet around said unit to said outlet, said reach-in rail having an inlet on the side of said rail facing the interior and an outlet on the side of said r-ail facing the ambient, said reach-in rail forming a heating chamber between said inlet and said outlet, and an electric heating element extending longitudinally in said reach-in rail and in heat exchange relation with said heating chamber and with said air curtain inlet.

14. A refrigerated display unit according to claim 13 including a divider partition between said heating chamber and a portion of said air curtain return passage, said heating element being located adjacent said partition, said divider partition being effective to prevent fluid communication between said heating chamber and said air curtain return passage.

15. An upright refrigerated display unit comprising:

a structure including wall portions for defining an interior storage volume having a front access opening; means for supplying cold air to said storage volume; said wall portions including a front wall defining the forward edge of said access opening;

a reach-in rail extending adjacent the upper edge of said front wall;

said rail forming a chamber that is substantially coextensive with the length of said rail;

means for producing an air curtain which flows across said access opening and which terminates at an air curtain inlet reg-ion extending along the forward edge of said access opening;

said inlet region being disposed within said front access opening and adjacent said reach-in rail;

said rail being open along at least a portion of the side thereof facing said inlet region and said storage volume for admitting to said chamber at least a portion of the air flowing in said air curtain;

said rail being provided with passages on a side thereof 15 facing outside said storage volume and toward the ambient region in front of said front wall for enabling air flow from said chamber to said ambient region; and

heating means in heat transfer relationship with said air. admitted to said chamber for warming said air prior to said fiow therefrom throughsaid passages.

References Cited UNITED STATES PATENTS 3,243,971 4/1966 Beckwith 62-256 WILLIAM J. WYE, Primary Examiner. 

1. AN UPRIGHT REFRIGERATED DISPLAY UNIT HAVING A FRONT ACCESS OPENING, SAID FRONT ACCESS OPENING BEING DEFINED BY SIDE WALLS, AND UPPER WALL, AND A LOWER FRONT WALL, SAID FRONT WALL TERMINATING AT A REACH-IN RAIL AT THE LOWER EDGE OF SAID ACCESS OPENING, A HEATING ELEMENT EXTENDING LONGITUDINALLY OF SAID REACH-IN RAIL AT AN UPPER PORTION THEREOF, AND A PROTECTIVE CAP EXTENDING AROUND SAID HEATING ELEMENT, SAID CAP HAVING A PLURALITY OF OPENINGS THEREIN. 